# std::ranges::drop_while_view<V,Pred>::drop_while_view

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< cpp‎ | ranges‎ | drop while view

drop_while_view() requires std::default_initializable<V> && std::default_initializable<Pred> = default; | (1) | (since C++20)
constexpr explicit drop_while_view( V base, Pred pred ); | (2) | (since C++20)

Constructs a `drop_while_view`.

1) Default constructor. Value-initializes the underlying view `base_` and the predicate `pred_`.
2) Move constructs the underlying view `base_` from base and the predicate `pred_` from pred.

### Parameters

base | - | underlying view
pred | - | predicate

### Example

Run this code

    #include <functional>
    #include <iostream>
    #include <ranges>

    int main()
    {
        static constexpr auto a = {-2, -7, -1, -8, -2, +-+8, 3, 1, 4, 1, 5};
        auto positive = [](int x) { return 0 < x; };
        for (auto v = std::ranges::drop_while_view{a, std::not_fn(positive)}; int x : v)
            std::cout << x << ' ';
        std::cout << '\n';
    }

Output:

    3 1 4 1 5

### Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR | Applied to | Behavior as published | Correct behavior
--- | --- | --- | ---
LWG 3714 (P2711R1) | C++20 | the multi-parameter constructor was not explicit | made explicit
P2325R3 | C++20 | if `Pred` is not `default_initializable`, the default constructor constructs a `drop_while_view` which does not contain an `Pred` | the `drop_while_view` is also not `default_initializable`

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